1. Field of the Invention
Exemplary aspects of the present invention relate to an image forming apparatus and a developer supplier, and more particularly to an image forming apparatus and a developer supplier for supplying a developer to be used for image forming at an increased speed.
2. Description of the Related Art
A related art image forming apparatus, such as a copying machine, a printer, a facsimile machine, or a multifunction printer including copying, printing, scanning, and facsimile functions, forms an electrostatic latent image on a photoconductor according to image data. The electrostatic latent image is developed with a developer (e.g., a toner) supplied from a development unit opposing the photoconductor to form a toner image on the photoconductor. The toner image is transferred onto a recording medium to form an image on the recording medium.
The toner to be used for development is supplied from a bottle containing the toner to a developer container of the development unit via a developer supplier. The developer supplier includes a temporary container for temporarily containing the toner supplied from the bottle and a conveyer for rotating to convey the toner in the temporary container toward the developer container. The developer supplier supplies the toner to the developer container to replenish it whenever the toner in the developer container is consumed for development. When the temporary container does not contain a sufficient amount of toner and thereby does not stably supply the toner to the developer container, the electrostatic latent image formed on the photoconductor may not be properly developed and a faulty image may be formed on the recording medium due to improper toner density.
To detect whether the temporary container contains the sufficient amount of toner or not, an exemplary developer supplier includes a sensor for detecting the toner at a specific height in the temporary container. When the sensor does not detect the toner at the specific height, the image forming apparatus notifies a user that the temporary container is almost empty and prompts the user to replace the bottle with new one. Therefore, the user may set the new bottle in the image forming apparatus before the temporary container becomes empty, preventing the faulty image from being formed on the recording medium due to improper toner density.
Another exemplary developer supplier includes an agitator for agitating the toner in the temporary container so as to prevent the toner from agglomerating and a driver for driving the conveyer and the agitator.
To form the image on the recording medium faster, the developer supplier needs to supply the toner to the development unit at an increased speed. When the conveyer is rotated at the increased speed to convey the toner faster, the agitator is also rotated at that increased speed because both the conveyer and the agitator are driven by the common driver.
The toner used in the image forming apparatus has a high flowability (i.e., a low accelerated agglomeration) so as to be conveyed at the increased speed. When the agitator is rotated at the increased speed, the agitator excessively agitates the toner in the temporary container. The toner is excessively dispersed in the air and is stirred up in the temporary container, and an amount of toner per unit volume decreases. The sensor detects the toner based on a load applied to the sensor by the toner. The excessively dispersed toner applies a decreased load to the sensor. Thus, the sensor may erroneously detect that the temporary container is almost empty even when the temporary container contains the sufficient amount of toner.